The present invention relates to magnetic resonance imaging and, more particularly, to a novel method of, and novel apparatus for, minimizing magnetic resonance (NMR) imaging motion artifacts due to power line interference.
It is well known that the power line signal alternating-polarity waveform can produce interference in any number of electronic systems. During nuclear magnetic resonance imaging, the energization of various system portions by power supplies receiving the power line waveform, will often allow artifacts related to the power line frequency (e.g. 60 Hz. in the United States) to have a deleterious effect on image quality. We have found that the ubiquitous nature of power line frequency signals requires that some form of synchronization be utilized to allow imaged data signal collection to take place over an integral number of power line frequency cycles for each imaging data collection sequence utilized in the magnetic resonance system. Only if such synchronized data collection occurs can the amplitude of the interference be made repeatable over each signal collection interval, so that the signal collection results can be suitably processed to essentially remove the artifacts and allow the resulting image to be essentially free of the line-frequency artifacts. It is highly desirable to provide methods of, and apparatus for, minimizing magnetic resonance imaging artifacts due to power-line-frequency interference.